Search

The paper introduces a robust methodology for evaluating complex electricity system efficiency, making several contributions. It systematically decomposes the electric power system into various processes, including power generation, transmission, distribution, and power consumption, with parallel sub-processes for production and domestic power consumption. Employing data envelopment analysis (DEA), the paper develops a network directional slacks-based (DSB) model to evaluate the whole system and the internal processes. The model is theoretically proven to be feasible, providing efficiency scores and identifying inefficiencies in the system and its processes. A noteworthy addition is the introduction of the DSB green Luenberger productivity index and its decomposition, offering an analysis of productivity changes in electricity systems. Empirical analysis covering 30 Chinese provinces from 2013 to 2019 uncovers the performance variations among provinces and processes, pointing out inefficiencies and changes in technology and efficiency over time. The empirical findings aim to support efforts in enhancing the overall efficiency of China's interprovincial power system. • We decompose the complex electric power system into four processes with dependence. • We build a network directional slacks-based (DSB) model for the complex power system. • We give a DSB green Luenberger productivity index (DPI) for our network model. • The efficiency score and DPI of the system are decomposed into those of processes. • We apply the model and indexes to electric power systems in Chinese provinces. [ABSTRACT FROM AUTHOR]

Background: Cardiogenic stroke has increasing morbidity in China and brought economic burden to patient families. In cardiogenic stroke diagnosis, echocardiograph examination is one of the most important examinations. Sonographers will investigate patients' heart via echocardiograph, and describe them in the echocardiograph reports. In this study, we developed a machine learning model to automatically identify diagnosis evidences of cardiogenic stroke providing to neurologist for clinical decision making.Methods: We collected 4188 Chinese echocardiograph reports of 4018 patients, with average length 177 Chinese characters in free-text style. Collaborating with neurologists and sonographers, we summarized 149 phrases on diagnosis evidence of cardiogenic stroke such as "" (severe mitral stenosis), "" (aortic valve degeneration) and so on. Furthermore, we developed an annotated corpus via mapping 149 phrases to the 4188 reports. We selected 11 most frequent diagnosis evidence types such as "" (mitral stenosis) for further identifying. The generated corpus is divided into training set and testing set in the ratio of 8:2, which is used to train and validate a machine learning model to identify the evidence of cardiogenic stroke using BiLSTM-CRF algorithm.Results: Our machine learning method achieved the average performance on the diagnosis evidence identification is 98.03, 90.17 and 93.94% respectively. In addition, our method is capable to identify the novel diagnosis evidence of cardiogenic stroke description such as "-" (mitral stenosis), "" (aortic valve calcification) et al. CONCLUSIONS: In this study, we analyze the structure of the echocardiograph reports and summarized 149 phrases on diagnosis evidence of cardiogenic stroke. We use the phrases to generate an annotated corpus automatically, which greatly reduces the cost of manual annotation. The model trained based on the corpus also has a good performance on the testing set. The method of automatically identifying diagnosis evidence of cardiogenic stroke proposed in this study will be further refined in the practice. [ABSTRACT FROM AUTHOR]

Modern meteorological observations in South China from 1960 to 2009 show a strong correlation between winter temperatures and two snowfall parameters, the southern boundary of the snow and the number of snowy days. Based on this relationship, the variation in annual winter mean temperature in South China from 1736 to 2009 was reconstructed using data acquired from Chinese historical documents dating from the Qing dynasty, such as memos and local gazettes. The reconstructed time series were used to analyse variations in winter temperature in South China. Significant interannual and interdecadal changes were found. The maximum temperature difference between neighbouring years was 3.1 °C for 1958-2009 and 3.0 °C for 1736-1957, whereas the maximum temperature difference between adjacent decades was 0.8 °C for the 1960s-2000s and 0.6 °C for the 1740s-1950s. The 2000s was the warmest decade; the mean temperature was 1.6 °C higher than that of the 1870s, which was the coldest decade between the 1740s and the 2000s. The mean winter temperature was warmer in the 18th and 20th centuries and coldest in the 19th century. [ABSTRACT FROM AUTHOR]

Zheng, J., Ding, L., Hao, Z. & Ge, Q. 2012 (January): Extreme cold winter events in southern China during AD 1650-2000. Boreas, Vol. 41, pp. 1-12. 10.1111/j.1502-3885.2011.00225.x. ISSN 0300-9483. We defined extreme cold winter events as those with occurrence probabilities lower than the 10th percentile of the probability density function, based on observed winter temperatures in southern China since 1951. Subsequently, we constructed impact severity levels using documentary evidence for those events during 1951-2000, considering three indexes for the freezing of rivers/lakes, widespread snow/ice storms, and cold damage to subtropical/tropical crops. Using these criteria we identified 50 extreme cold winters for the period AD 1650-1949 based on ∼4000 pieces of comparable information extracted from local gazettes in southern China, after verification using data from three weather stations with long records. It was found that the frequencies of the extreme cold winter events since 1650 varied over time. The most frequent occurrences were found during AD 1650-1699 and in the first and second halves of the 19th century, with frequencies twice as high as in the second half of the 20th century. In contrast, the frequencies of extreme winters during the 18th century were close to that in the second half of the 20th century. High frequencies of extreme cold winters in AD 1650-1720 and AD 1795-1835 occurred during the sunspot Maunder and Dalton Minima. The intensities of some historical cold events, such as those during 1653-1654, 1670, 1690, 1861, 1892 and 1929, exceeded those of the coldest winter events since 1951. [ABSTRACT FROM AUTHOR]

Objective: To study the age-specific distribution of antimüllerian hormone (AMH) and describe the association of AMH with androgenic and metabolic profiles at different ages.Design: Cross-sectional study.Setting: University hospital.Patient(s): A total of 6,763 Chinese women from birth to menopause.Intervention(s): None.Main Outcome Measure(s): Anthropometric parameters (height, weight, and blood pressure), and levels of AMH and testosterone, glucose metabolism, and lipid profiles.Result(s): According to the level of AMH, four age phases were established: childhood (0-10 years), adolescence (11-18 years), reproductive age (19-50 years), and advanced age (≥51 years). During childhood and adolescence, AMH levels increased, reaching a peak at 18 years. A decline occurred thereafter during the reproductive-age period until the age of 50 years, and it remained at a low level above 0 onward. We found that AMH was negatively correlated with testosterone in childhood (r = -0.25), but was positively correlated with testosterone and the free androgen index in adolescence (r = 0.30; r = 0.26, respectively) as well as during the reproductive phases (r = 0.28; r = 0.31, respectively). No correlation was observed between AMH and body mass index, fasting blood glucose, fasting insulin, the homeostasis model assessment, total cholesterol, triglycerides, low-density lipoprotein, or high-density lipoprotein at any phase.Conclusion(s): From birth to 18 years, AMH increases, then it declines thereafter, indicating changes of ovarian maintenance. A positive relationship between androgenic profiles and AMH during adolescence and reproductive years implies a synchronism between androgens and ovarian reserve. [ABSTRACT FROM AUTHOR]

Background: Hemodynamic impairment of blood pressure may play a crucial role in determining the mechanisms of stroke in symptomatic intracranial atherosclerotic stenosis). We aimed to elucidate this issue and assess the impacts of modifications to blood pressure on hemodynamic impairment., Methods: From the Third China National Stroke Registry III, computed fluid dynamics modeling was performed using the Newton-Krylov-Schwarz method in 339 patients with symptomatic intracranial atherosclerotic stenosis during 2015 to 2018. The major exposures were translesional systolic blood pressure (SBP) drop and poststenotic mean arterial pressure (MAP), and the major study outcomes were cortex-involved infarcts and borderzone-involved infarcts, respectively. Multivariate logistic regression models and the bootstrap resampling method were utilized, adjusting for demographics and medical histories., Results: In all, 184 (54.3%) cortex-involved infarcts and 70 (20.6%) borderzone-involved infarcts were identified. In multivariate logistic model, the upper quartile of SBP drop correlated with increased cortex-involved infarcts (odds ratio, 1.92 [95% CI, 1.03-3.57]; bootstrap analysis odds ratio, 2.07 [95% CI, 1.09-3.93]), and the lower quartile of poststenotic MAP may correlate with increased borderzone-involved infarcts (odds ratio, 2.07 [95% CI, 0.95-4.51]; bootstrap analysis odds ratio, 2.38 [95% CI, 1.04-5.45]). Restricted cubic spline analysis revealed a consistent upward trajectory of the relationship between translesional SBP drop and cortex-involved infarcts, while a downward trajectory between poststenotic MAP and borderzone-involved infarcts. SBP drop correlated with poststenotic MAP negatively (r s =-0.765; P <0.001). In generating hemodynamic impairment, simulating blood pressure modifications suggested that ensuring adequate blood pressure to maintain sufficient poststenotic MAP appears preferable to the reverse approach, due to the prolonged plateau period in the association between the translesional SBP drop and cortex-involved infarcts and the relatively short plateau period characterizing the correlation between poststenotic MAP and borderzone-involved infarcts., Conclusions: This research elucidates the role of hemodynamic impairment of blood pressure in symptomatic intracranial atherosclerotic stenosis-related stroke mechanisms, underscoring the necessity to conduct hemodynamic assessments when managing blood pressure in symptomatic intracranial atherosclerotic stenosis., Competing Interests: Disclosures None.

Background: Overweight and obesity are epidemic worldwide. Our previous study found that the prevalence of overweight and obesity in primary students is high., Objective: we sought to estimate whether the prevalence of overweight and obesity among university students is still high in China., Methods: A cross-sectional study was designed to collect the routine health screening data for university students in 2013. The height and weight of students were measured, and BMI was calculated with height and weight, we estimated the underweight and obesity prevalence of university students using by two references [Working Group on Obesity references in China (2004) and World Health Organization (WHO) criteria (2000)]., Results: Depending on the China references used, the overall prevalence of underweight, overweight (including obesity) and obesity in male university students were 14.2%, 14.7% and 4.2%, respectively; in female university students were 27.5%, 4.4% and 0.6%, respectively. Depending on the WHO references used, the overall prevalence of underweight, overweight (including obesity) and obesity in male university students were 14.2%, 11.5% and 2.5%, respectively, in female university students were 27.5%, 2.4% and 0.3%, respectively. An interesting observation made was that the underweight prevalence of university students has an increasing trend, especially in female., Conclusion: The study showed that the prevalence of underweight in university students, especially in female students has become a critical health issue. Related department of school and government should pay more attention to student's physical health., (Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.)

Background: Previous study revealed that the link between dental caries and obesity has been controversial. The purpose of this research is to investigate the association between dental caries and obesity among primary school children in Wannan area, China., Methods: A cross-sectional study was designed to collect the routine health screening data for primary school children aged 5-14 years in Wannan area,China, Overweight and obesity status were determined using the International Obesity Task Force standard (IOTF) BMI cut-off points. Caries status was recorded based on WHO recommendations., Results: Our results revealed that the overall caries prevalence of the subjects was 44.9%, Maximum number of caries affected children belonged to underweight and normal group, followed by overweight, and the least number was obesity. These differences were statistically significant (chi-square test, P < 0.001). Children with obesity were 1.908 times (OR =1.908; CI95%=1.750, 2.079) more likely have caries than children with underweight or health weight. Overweight children were 1.547 times (OR = 1.547; CI95% = 1.479, 1.618) more likely to have caries than children with underweight or health weight. After adjusted the gender and age, a statistically significant association was also observed between body mass index categories and caries., Conclusions: Obesity may have a significant effect on caries prevalence of primary school children in Wannan area, China. The importance of obesity should not only be emphasized with respect to general diseases but also with regard to carious lesions., (Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.)

Previous studies revealed that low calcium intake is related to high prevalence of cardiovascular diseases such as hypertension. However, the relationship between serum calcium and blood pressure was unclear. The prevalence of hypertension is high in China. Thus, the aim of this study was to evaluate the serum calcium level between hypertensive and normotensive groups and to investigate the correlation between serum calcium, blood pressure, and blood lipid parameters. A total of 1,135 adult subjects participated in this study and were divide into two study groups: a hypertensive group (n = 316) who had 140 mmHg or higher in systolic blood pressure (SBP) or 90 mmHg or higher in diastolic blood pressure (DBP) and an age- and sex-matched normotensive group (n = 819, 120 mmHg or less SBP and 80 mmHg or less DBP). Our results indicate a significant trend for men (60 years old or older) in the direction of decreasing blood pressure with increasing serum calcium level, but no trend for women was indicated. In the normotensive group, a significant positive correlation was found between DBP and total cholesterol (P < 0.01) and triglyceride (P < 0.01), Likewise, triglyceride was positively correlated with SBP (P < 0.01). Overall, these data suggest that serum calcium may have an influence in the blood pressure of older male subjects with hypertension and in blood lipid profiles of normotensive subjects.

Background: Numerous studies have reported that low calcium intake is related to a higher prevalence of cardiovascular disease. However, the relationship between serum calcium and coronary heart disease is unclear. The purpose of this study was to compare serum calcium levels in patients with coronary heart disease and those in healthy individuals., Methods: This retrospective, case-control study conducted in the People's Republic of China comprised 380 cases and 379 controls. Serum calcium levels, blood lipids, and anthropometric measurements were measured in both groups. The Student's unpaired t-test or Chi-square test was used to compare differences between cases and controls. Pearson's partial correlation coefficient was used to determine the association between serum calcium, blood lipids, and blood pressure in both groups., Results: Our results indicate that the average level of serum calcium in cases was higher than in controls. Serum calcium levels showed no correlation with any parameter except for triglycerides in either group., Conclusion: Overall, these data suggest that serum calcium has no influence on coronary heart disease or triglyceride levels in the general population.

This is a retrospective, observational study to evaluate the effect of maternal age on the outcomes of in vitro fertilization and embryo transfer (IVF-ET). 11830 IVF-ET cycles from 10268 women were included. Four groups of different maternal age periods were compared. The groups were 21-30 years old group (4549 cycles), 31-35 years old group (4424 cycles), 36-40 years old group (2429 cycles), and over 40 years old group (428 cycles). The mean starting dose of Gn and mean total dose of Gn in each cycle were significantly higher (P<0.01), while the mean retrieved oocyte number was significantly lower (P<0.01) in groups of higher maternal age period than those in each of the lower groups. The biochemical pregnancy rate and the clinical pregnancy rate were significantly lower (P<0.01), while the miscarriage rate was significantly higher (P<0.01) in groups of higher maternal age period than those in the lower groups. No difference was found in two-pronuclear zygotes (2PN) rate and good quality embryo rate among different groups. Birth defect rate was also comparable in the born babies in different groups. In the group with patients' age over 40 years old, the pregnancy rate was 26.87%, the clinical pregnancy rate was 19.39%, while the miscarriage rate after clinical pregnancy was 36.14%. To draw the conclusion, patients with higher maternal age had worse IVF outcomes. In women of fertile age, patients between 20 and 30 years old have the best IVF outcomes. Patients over 40 years old have poor IVF outcome and high miscarriage rate, which suggested the necessity of preimplantation genetic screening (PGS).